Method for twisting crank shafts



Dec. 13, 1932.

H. M. WOLFE ET AL METHOD FOR TWISTING CRANK SHAFTS Original Filed March 2. 1927 v 4 Sheets-Sheet 1 V INVENTORJ flw/ev 4 0: {mama/WM Max/a1 4 Dec. 13, 1932. H. M. WOLFE ET AL METHOD FOR TWISTING CRANK SHAFTS Original Filed March 2. 1927 4 SheetsSheet 2 l l lllll Dec. 13, 1932. M L 1,890,635

METHOD FOR TWISTING CRANK SHAFTS 'Original Filed 2 1927 4 Sheets-Sheet 3 Dec. '13, 1932. W LF A 1,890,635

METHOD FOR TWISTING CRANK SHAFTS Original Filed March 2. 1927 4 Sheets-Sheet 4 Patented Dec. 13, 1932 UNITED STATES) PATENT OFFICE;

HENRY M. WOLFE-AND CORRINGTON A. NICHOL, OF MUSKEGON, MICHIGAN, T CONTINENTAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, A CORPORATIQN OF VIRGINIA METHODFOR TWISTING CRANK SHAFTS Original application filed March 2, 1927, Seria1 1\To. 171,945. Divided and this application filed March 8, 1929. Serial No. 345,294.

This invention relates to the metal working art and refers more particularly to a method and machine for use in, the manufacture of crankshafts, especially where it .is desirable to twist one or more of the crankshaft throws into position. i

Among the objects of our invention is the provision of an improved method of manufacturing crankshafts, tending to simplify .the steps involved and reduce the ultimate manufacturing-cost A furthervfeature liesin providing a machine vfor performing a twisting operatlonon the crankshaft, our machine be ng comparatively simple in op- .eration and capable of construction at relatively low cost. Our machine may be operated efficiently at low cost, and being substantially automatic in its operation requires very little attention on the part of the operator.

One feature of our inventlon resides in the provision of means whereby a portion of the crankshaft to beltwisted is automatically clamped by the twisting mechanism under remote control, no manual attendance being necessary to operate this portion of the mechanism. We believe this feature as well as other features which will be described hereinafter, to be broadly novelin this art. One

convenient embodiment of our invention has been shown in our accompanying drawings in whichthe operator need only move a control so as to cause the clamping device to automatically clamp a portion of the crankshaft, such portion after the clamping op eration, being twisted by the clamping device.

'We have illustrated our lnvention in connection with a seven bearing six throw crankshaft although it will be understood that our tions ofthe various parts of the machine showing the twisting mechanism which tend toward simplicity, economy.

This application is a division of our cor.

efficiency, and

pending application Ser. No. 171,945 filed:

March 2, 1927. The claims in our parent application are directed to our machine and in this divisional application the claimsare directed to our method.

Referring to. the accompanying drawings.

indicate ing position about to commence its twisting operation,

Fig. 2 is a front elevation of the machine pletion of its twisting stroke,

Fig. 3'is a plan view of themachinewithw the cylinder, associated with the crankshaftholding mechanism, partly brokenaway, Fig. 4 is a detail side elevation of :the clamping and twisting mechanism inposition to receive a crankshaft, Fig. 5 is a rear elevation of the mechanism shown in Fig. 4:,

Fig. 6 is an elevation view showing the position of the twisting mechanism at the completion of its movement and further illustrating the latch mechanism associated withthis portion of the machine,

Fig. 7 is a plan view of one of the twisting elements, 8 is a side viewof the other twisting element, I i

Fig. 9 is a front view thereof,

Fig. 10 is a perspective View of the bell,

crank forming the connection betweenithe, twisting elements,

Fig. 11 is an end view ofthe crankshaft before the twisting operation, v i Fig. 12 is a like view of the completed at the com crankshaft after the twisting operation, and I Fig. 13 is a side elevation of the crankshaft shown in Fig. 12.

In carrying out our invention we prefer to first forge in one or more operations certain of the crank throws into their final positions, simultaneously fashioning all of the throws,

ing machine in detail.

cheeks, and bearings with certain of the throws in a position to be twisted.

Crankshafts in general may ordinarily be completely forged in position but a saving in die cost and machining operations, as well as other advantages, is'brought about by our invention. In the instance of the particular crankshaft illustrated reference character A represents the shaft having the throws 16 inclusive, bearings 713 inclusive, and checks 1425 inclusive. The throws in this type of crankshaft are ordinarily arranged as shown in Figs. 12 and 13, the pairs of throws indicated being 120 apart. In Fig. 11 we have shown the crankshaft with our preferred arrangement of throws forged in position as will readily be understood. Thus the crankshaft before operation of the twisting machine has the throws 1, 6, 2, 5 forged in their ultimate respective positions, the throws 3, 4 being fashioned during the forging operation preferably substantially 90 fromtheir ultimate positions as shown in Figs. 12 and 13. If desired, these throws 3, 4 might be forged in other positions, forultimate swinging or twisting, but we prefer to locate these throws as indicated. 7

In producing the forging shown in Fig. 11 the stock might be first cut out to desired length, heated suitably for working, subjected to'an edger operation to roughly fashion the crankshaft throws in a single plane, all of these steps being well known in the art. The forging might then be subjected to forging dies to produce the crankshaft shown in Fig. 11. This forging might then be trimmed to remove the excess metal at the die parting line and then restruck to remove excess draft to facilitate machining although this latter step is not deemed necessary for the successful production of crankshafts. The crankshaft is then subjected to the twisting operation by our machine whereby throws 3, 4 are swung into their proper relative positions shown in Figs. 12 and 13. The crankshaft may then be restruck in the well known manner to further insure proper alignment of thevarious elements of the crankshaft. We have found however thatour twisting machine operates to such a degree of accuracy that the restriking operation might well be dispensed with, such operation being desirable from a standpoint of further insuring that the shaft is in alignment. The entire method as outlined may be accomplished in one heating of themetal, our twisting machine ,being capable of speedily receiving, twisting, and discharging thecrankshaft.

We will now describe our improved twist- This machine comprises a ma n casting B having a bed 26 receiving lower fixed holding elements 27, 28 respectively cooperating with upper relatively movable holding elements 29, 30. These pairs of holding elements are preferably formed with suitable recesses and projections confirming with the surface contour of the end pairs of throws with associated cheeks and bearings whereby upon downward movement of the upper holding elements the crankshaft is firmly held with the center throws 3, 4 exposed for twisting preferably as a unit about bearings 9 and 11.

For controlling the movement of the holding element 29 and 30 any suitable mechanism might be provided. For example, we have provided a head 31 slidable vertically 011 guides 32, the head carrying the movable holding elements and actuated by a toggle linkage 33. The levers of the toggle 33 are respectively pivoted at their ends 34, 35 to the frame B and slide 31, the central pivot 36 being actuated by a piston rod 37 connected with piston 38 operating in cylinder 39 supported on pivotal bearings 40 to compensate for the angular travel of the pivot point 36 about the point of swinging 34. When it is desired to hold the crankshaft in position for a twisting operation, fluid under pressure, conveniently air, is admitted from supply pipe 42 to the forward side of piston 38, the air being controlled in any suitable manner such as by a two way valve C of ordinary suitable commercial design. Thus by moving valve handle 41, air passes from the valve to the pipe 42 leading to the inside of the cylinder to the forward side of the piston. Simultaneously, the movement of handle 41 serves to exhaust any fluid behind the piston by wayof exhaust pipe 43. The pipes 42 and 43 also function respectively as exhaust and inlet pipes upon proper actuation of the handle 41, a suitable vent being provided for the exhausted air at the valve C or other convenient point, The details of the valve are not important since any well known suitable valve might be used. In order to hasten the movement of the piston 38 we have provided an auxiliary exhaust pipe 44 controlled by a valve D suitably operated at the proper time from'handle 41 as by a link 45.

A second air cylinder 46' is provided, likewise pivoted at 47 to afford a pivotal movement about a horizontal axis. Within this cylinder is located an'operating piston 47 which may be similar in'construction with the piston 38. This piston actuates the piston rod '48 pivoted by a pin 49 between the forked end 50 or bell crank lever E, the latter being pivoted by a pin 51 carried between the arms 52 of the clamping twisting element or base F. The other end 53 of bell crank E'operates between the forks 54 of the complementary clamping twisting element or cap G, a pin 55 establishing pivotal connection of these parts by reason of pin bearings56, and 57. The end 53 has a face 58 engageable with aface 59 of element G in one direction of rocking of the bell crank and like cooperating faces 60 and 61 provided for engagementin the other directioao rocking; of the bell crank. The complementary clamping twisting elements; F1 and G together provide a twisting block The element F is formed with, flanges ortrunnions.62 havinga rotatable bearing .63.; in a block v64 fixed with respect to the-bed of the machine. The element G has .a clamping; twisting face for overlying and cooperate ing withthe clamping-twisting face66, these faces,-.like the holding; elementsv27', .29. to-. gether conforming with. the surface. contour of the. crankshaftso as to: cooperate to. enclosethe portion of the crankshaft tobe twisted.

With the parts in the positionfshownin Fig. 4 the forged crankshaft, ready for the tWisting operation, may be'placedinvtheu machine, the faces of the holdingmembers27-,"

28 and clamping twisting elementF providing for nesting of the :crankshafttherein, as

will be readily understood. It will be noted that the element G is located clear from interference with placement of the crankshaft.

"The lever 41 is actuated to produce a lowering of the head 31 whereby the crankshaft ends are firmly gripped.

Air is then introduced at the rear of cylinder 46 by movement of hand lever 67 act- "ing through a valve C to admit air from supply line 68 to outlet 69. The first part of the movement of piston rod 48 to the left (as shown in Figs. 1 and 4) swings the bell crank E counter clockwise on its pivot 51 swinging element G into the positlon shown in Fig. 1, without movement of the element F which offers greater resistance to movement because of engagement by the crankshaft. As soon, however, as the element G has been swung to engage the crankshaft, this relative position of the twisting clamping elements being shown in Fig. 1, continued movement of the piston rod 48 will swing the elements F, G, clockwise within bearing 63,

" through an arc of 90 twisting and positioning the throws 3, 4 in a position 120 from the other throws as shown inFigs. 2, 12 and 13.

In order to accurately limit the angular twisting movement of the crankshaft twisting elements so as to accurately twist the throws through the exact desired angle, we have provided one or more adjustable stops 7 O engageable with the element F. Before rotating the twisting elements back to the initial position it is desirable to arrange the return movement of the actuating piston so as to first hold element F fixed until element G is moved free from the crankshaft, whereupon both clamping elements may be rotated free from engagement with the twisted crankshaft. To this end a latch 71 is pivoted at 72 to a fixed bracket 73, the latch being urged upwardly by spring 74 so as to automatically j engage the latch nose 75 in a recess 76 in the .into a position relative to the element F as lower end of both of the arms 52 of twisting opposite end of the cylinder. Thus the pie ton rod48 will be moved to the right or rearwardly, the initial portion of the returnstroke swinging bell crank E clockwise about 7 its pivot 51 whereby the clamping element G will be swung entirely clear of the crankshaft shownin Fig. 4, although it will be under. stood that in this figure the end of-the return stroke has been reached; This swing--- ingmovement of elementG may be limited f by engagement of sl1ouldei s; 77 onthe arms- 77 of the angle-stops 7 7 secured alongthe edges of arms 52 of element ,Fas best shown: in Figs. 4and 5. This initial portion of the 1 return stroke, after latch 71 has held element F stationary while element G has swung clear ofthe crankshaft, movesaqtrip 78, carried, by the bell crank E, into. contact with the; lug 79 whereby, when the elementG has cleared the crankshaft, the latch 71 will be tripped against the actionof spring 74, mov-,

'ing-the nose 75 clearof the recess-76; 0011-.

tlnued movement of the piston rod will then swing the elementsF andG counterclockwise into theposition shown in Fig. 4 ready to. receive another crankshaft. 80 represents a stop. preferably adjustable, having an end, 81 within the cylinder for limiting the rearward movement of the pistonwithin cylinder46. Duringthis return movement, the throws 3,4 havingbeen twisted upwardly, the clamping twisting elements return entirely-.- clear of thecrankshaft, which is still preferablvheld by the end holding elements.

The holdingelements-may then be released from engagement. with the crankshaft by suitablyanoving the valve lever 41 to cause piston- 38 to move slide upwardly. The. twisted crankshaft may thenbe removed from the machine and subjectedto arestriking opera-. tion, if desired. Throughout, the entire method of operations thecrankshaft bearings are preferably aligned at all times.

Itwill thus benotedthat we haveprovided a novel method. of forming crankshafts. Our machine for performing the twisting operation. is simply constructed and is especially adapted for quickly and accurately twisting the desired throws. If desired other power means may be arranged for causing movement of the holding and clamping elements and the. scope of our invention is :not intended to be-limited to the specific showing. ofthese and other features of our invention. Among the featuresof novelty of our machine is the mannerfin-which we;

effect an automatic clamping of one or more of the throws without requiring an attendant to manually apply or look the clamping mechanism. Furthermore by simply operat- 5 ing the power control, our machine automatically applies the twisting clamp and then produces the twisting operation. Another feature of novelty resides in the latch mechanism which is automatically responsive to :movement of the twisting mechanism.

Our machine and methodmay be conveniently adapted. to many other styles of crankshafts than the particular style illustrated. It is to be understood that the holding and twisting elements areprovided with faces fashioned like dies to correspond to the contour of the crankshaft to be twisted; also it may be found desirable to twist other of the throws into final position. Certain features of our machine could be incorporated to advantage where a plurality of twisting units are employed, each of which could be caused to automatically clamp and twist the desired portions of the crankshaft. Our invention is applicable to crankshafts having a plu- Y rality of throws and wherein it is desired to ultimately fashion and position the throws at a relatively angu ar position. Thus the various throws might be forged in a common 303 plane with certain of the throws out of the ultimate desired position and finally twisted into proper relation by one or more pairs of our twisting clamping elements.

hat we claim as our invention is:

1. A method of forging and twisting six throw crankshafts consisting in forging said crank shaft placing the first, second, fifth and sixth throws in their ultimate posit ons, all

taneously fashioned substantial y in final form, then subjecting the forging while heated to a device holding the positioned throws in a manner preventing their distortion, while at thev same time twisting the third and fourth throws into their ultimate pos1- tion relative to the positioned throws in a then subjecting the forging while heated to a 7 device holding the heated positioned throws in a manner preventing their distortion, while at the same time twisting the remain ng throws into their ultimate position relative to the positioned throws in a manner preventing their deformation during the twisting operathe throws. cheeks, and bearings being simul- -tioi1 and maintaining the shaft bearing in axial alignment during the twisting opera tion.

3. A method of forging and twisting a six throw crankshaft consisting in forging the shaft to fashion the throws with the shaft bearings in axial alignment, the two end pairs of throws being thereby forged to lie in their ultimate positions and the central pair of throws lying in a plane substantially 90 from the desired ultimate plane of location, then holding the end pairs of throws against relative rotative movement and twisting the central pair of throws through an angle of substantially 90 to their ultimate desired position while maintaining the shaft bearings in axial alignment.

In testimony whereof, we have hereunto set our hands and seals, this th day of February 1929.

HENRY M. WOLFE. CORRINGTON A. NICHOL. 

